Pneumatic support structure

ABSTRACT

Disclosed is a support structure comprising a tension-compression element ( 1 ) which is composed of tension-compression bars ( 2 ) that are connected in real joints ( 3 ) as well as tension straps ( 4 ) that extend from one joint ( 3 ) to another ( 3 ). The outermost tension-compression bars ( 2 ) are connected in one respective knot ( 9 ). Two pressurized hollow members that are surrounded by a cover ( 6 ) are arranged on both sides of a plane that extends through the tension-compression element ( 1 ) such that the linear tensions σ generated in the cover ( 6 ) preload the tension straps ( 4 ) on the plane of the tension-compression element ( 1 ), secure the tension-compression bars ( 2 ) against bending, and stabilize the joints ( 3 ). The linear tensioning components that extend perpendicular to said plane of symmetry strut the tension-compression element ( 1 ) against lateral bending. Air-tight, optionally elastic pneumatic elements ( 7 ) can be inserted into the hollow members ( 5 ).

The present patent application relates to a foldable pneumatic supportstructure according to the introductory clause of Claim 1.

Several pneumatic support structures are known, also those with afoldable or rollable compression bar; likewise, support structures areknown in which the compression bar or the compression bars can be joinedtogether from individual elements. Thus, a pneumatic structure is knownfrom EP 1 210 489 (D1), in which the compression bars can be joinedtogether. In EP 04 716 193 (D2), the compression bars are constructed sothat they can only receive compressive forces after the pneumaticstructures are filled with compressed air. In the empty state, thedescribed support structures are able to be rolled with bending radiiwhich are not too small. In addition, from CH 02074/05 (D3) a pneumaticsupport structure is known, which has two tension-compression elementsrunning longitudinally, which at the same time constricts the pneumaticstructure in the manner of a double spindle, whereby on the one hand apreloading of the tension-compression elements is achieved with, at thesame time, a greatly increased bending rigidity, and on the other handthe lateral stabilizing of the tension-compression elements is improved.For each of the essential features, each one of the said citations isregarded as the closest prior art.

The disadvantage of the above-mentioned compression bars is evident fromall three said publications: The described pneumatic support structuresare not really foldable, or the effort which must be made by theinsertion of the dismembered individual parts of the compression bars,is great, and the precise positioning thereof is difficult.

The object of the present invention consists in providing a reallyfoldable pneumatic support structure which, during unfolding, has aprecisely positioned compression bar without external addition and henceovercomes the disadvantages of the known solutions.

The solution to the problem which is posed is expressed in thecharacterizing clause of Claim 1 with regard to its essential featuresand in the following claims with regard to further advantageousfeatures.

The invention is described in further detail in several exampleembodiments in the enclosed drawings, in which:

FIG. 1 shows the side view of a first example embodiment,

FIG. 2 shows a cross-section through the first example embodiment,

FIG. 3 shows an isometric view of the first example embodiment,

FIG. 4 shows a foldable tension-compression element of the first exampleembodiment,

FIG. 5 shows a second example embodiment of a foldabletension-compression element in a side view,

FIG. 6 shows a third example embodiment of a foldabletension-compression element in a side view,

FIG. 7 shows a fourth example embodiment of a foldabletension-compression element in a side view,

FIG. 8 shows a two-dimensional support framework with fourtension-compression elements,

FIG. 9 shows a two-dimensional support framework with threetension-compression elements,

FIG. 10 shows an areal support framework with six tension-compressionelements in quadrilateral form,

FIG. 11 shows an areal support framework with nine tension-compressionelements in triangular form,

FIG. 12 shows a fifth example embodiment of a foldabletension-compression element in a side view,

FIG. 13 a-d show illustrations of an areal support framework in the formof an umbrella,

FIG. 14 shows an isometric view of a variant to FIG. 13,

FIG. 15 shows an isometric view of a second variant to FIG. 13.

FIG. 1 is the diagrammatic illustration of a first example embodiment ofthe idea of the invention. A tension-compression element 1 is composedof several compression-pressure bars 2 which are connected with eachother articulatedly in joints 3, and several tension elements 4. Forexample, wires, chains, cables or straps, hereinafter named tensionstraps 4, run between the joints 3. In the illustration according toFIG. 1, the axes of the joints 3 run perpendicularly to the plane of thedrawing. The tension straps 4 are preferably constructed as wire cablesand are flexible without bending. The use of tension straps 4 made oftextiles or plastics, metals, and combinations of such materials, forexample aramid fibres or similar materials, is likewise in accordancewith the invention. Instead of in the joints 3, the tension straps 4 canalso be fastened adjacent thereto. Instead of single tension strap, thenrespectively two thereof can be present, which cross over each otherwhen the fastening takes place on the upper chord and lower chordalongside the joints. A possibility also exists in the fastening of thetwo straps on the joint on the upper chord or respectively lower chordand on the adjacent tension-compression bars of the corresponding jointof the lower chord or respectively upper chord.

In this illustration, the elements designated by 2, 3, 4 form a flatframework and are constructed as such for loads→F acting vertically fromabove. As a variant of the framework illustrated in FIG. 1, a variantwhich is not illustrated is likewise included in the idea of theinvention, in which the tension-compression bars 2 are constructed to beof different length, with the restriction that respectively for each oneillustrated lying above in FIG. 1 (i.e. situated in the upper chord 11),an equally long one, lying below in FIG. 1 (i.e. situated in the lowerchord 12) is incorporated at the homologous location.

In this example embodiment, such a tension-compression element accordingto FIG. 1 is inserted into the plane of symmetry of a pneumatic element5, as is illustrated as a cross-section in FIG. 1. This pneumaticelement 5 consists of a cover 6 having tensile strength, into which forexample two tube-like hollow members 7 are inserted, which are made ofelastic and gas-tight material. Other solutions are likewise inaccordance with the invention, but require a certain effort for sealingthe pneumatic element 5 with respect to the tension-compression element1 and the tension straps 4. For example, the two hollow members 7 can beconnected or basically constitute only a single hollow member which hassuitable ducts for the mechanical parts. Likewise, the cover 6 and thehollow member can be a single element when suitable seals areincorporated.

The cover 6 can also be connected with the tension-compression bars 2 bymeans of pockets, as illustrated in the lower part of FIG. 2. Throughthe linear tensions which act in the covers 6, the upper chord 11 andlower chord of the tension-compression element are stabilized laterally,because the covers apply there with their linear tensions with generallysymmetrical tension forces to the left and to the right. The vector sumsof these linear tensions act upwards and downwards (with respect to FIG.2) and generate in the tension straps 4 tension forces which preloadthem. These tension straps 4 are therefore able to receive compressionforces→F acting from the exterior (cf. FIG. 1), until the saidpreloading forces acting on them are compensated by the distributedcompression force→F.

The pressure gas thereby undertakes three tasks:

-   -   stabilizing the joints 3,    -   stabilizing the tension-compression bars 2 against bending,    -   erecting the structure from the folded position.

FIG. 3 shows such a support structure according to the invention inisometric view, omitting the elastic hollow members 7. At the ends ofthe said tension-compression element, the outermost tension-compressionbars 2 are each joined together in a knot 9, optionally detachably.

FIG. 4 shows only the tension-compression element consisting oftension-compression bars 2 and tension straps 4 in the relieved andunloaded state, partially folded together. In the relieved state, thetension straps 4 are slack.

The illustration of FIG. 4 refers to the same tension-compressionelement as that of FIGS. 1 and 3. In this construction, thetension-compression element can be folded without the connections withthe knot 9 having to be loosened.

FIG. 5 is the diagrammatic illustration of a second example embodimentof a foldable tension-compression element. Whereas the construction ofthe pneumatic element 5 (not illustrated here) is substantially thesame, the differences of the various example embodiments lie primarilyin the development of the tension-compression element. Here, thetension-compression element consists of three pairs oftension-compression bars 2, all of the same length l, in which thelength of the tension straps increases towards the centre. Adjacent tothe knots 9 in the so-called upper chord 11—in FIG. 5 thetension-compression bars 2 illustrated above—in each case atension-compression bar 2 of length l is connected with atension-compression bar 2 of length b in the lower chord 12, in whichthe condition b>l applies. In so far as this condition is maintained,the tension-compression element can be folded without loosening theconnections in the knots 9. As in the previous, second, exampleembodiment, the joints 3 are again connected by tension straps 4. If thevariant is selected with two tension straps 4, optionally crossing overeach other, which are fastened to the upper chord and/or lower chordalongside the joints on the tension-compression bars, the connection inthe knots 9 must optionally be loosened for folding thetension-compression element 1.

In FIG. 6 a third example embodiment is illustrated of atension-compression element according to the invention. Here, thetension straps 4 run respectively from the centre of eachtension-compression bar 2 to the opposite joint 3. Two shorttension-compression bars 2 of the length b are connected in each case tothe two knots 9, whereas all the other tension-compression bars 2 havethe length l. A tension strap 4 of the length h* is arranged in eachcase adjacent to the knot 9. So that the illustrated tension-compressionelement is able to be folded, the condition

h>h*>l/2

applies for h*.

As a further condition for the foldability, in this example embodimentit applies that the connection of each of the two tension-compressionbars 2, which converge in the knot 9, can be loosened.

In the example embodiment according to FIG. 7, the tension straps 4again run respectively as in the previous example embodiment, from thecentre of each tension-compression bar 2 to the opposite joint 3. Allthe tension-compression bars 2 are of the same length l with theexception of those lying above in FIG. 7, adjoining the knots 9. Theseeach have a length b<l. In order to make possible the foldability of thetension-compression element according to FIG. 7, again two tensionstraps are provided with a condition:

h*>l/2.

In addition, here also the connection of the adjacenttension-compression bars 2 in the knot 9 must be loosened. For thelengths h of the other tension straps 4, the following applies

h>h*.

In FIG. 8 to 11, support structures according to the invention areillustrated, which extend in two dimensions and therefore basicallyconstitute areal support frameworks. Thus, FIG. 8 shows a first arealsupport framework which is constructed from four support structuresarranged in a rectangle 13. The support structures coming into use herecan consist of one of the example embodiments already illustrated. Theyare respectively connected with each other in the knots 9 and form therea real or virtual joint 10. The said rectangle 13 is spanned by asuitable membrane 14 and forms therewith for example a roof or a screen.Possible drains for rainwater are not illustrated, but can be providedat suitable locations.

In an analogous manner to FIG. 8, in the example embodiment according toFIG. 9 a triangle 15 is formed from three—not necessarilyidentical—linear support structures, again according to one of thepreviously described example embodiments. Here, also, a taut membrane 14covers the support structure.

The tensile stresses occurring in the example embodiments according toFIG. 8, 9 and hence tilting moments and lateral bending moments in thetension-compression elements 1 can be at least partially compensated bythe fastenings in the joints 10 and by a wider development of thetension-compression bars 2.

FIG. 10 is the illustration of an areal support framework according tothe invention. It is constructed from six basically similar foldabletension-compression elements 1, for example from that according toFIG. 1. The half of a cover 6 with an elastic hollow member 5 (notillustrated) lying therein is arranged respectively on the outer side ofeach tension-compression element. In the four fields between thefoldable tension-compression elements 1, four air chambers 16 arearranged, which are either connected in a gas-tight manner to thetension-compression elements 1, or are provided in turn with elastic andgas-tight hollow bodies. As the radii of curvature of the covers 6 andof the air chambers 16 are greatly different and the linear tension intheir covers runs proportionally to the pressure and to the radius ofcurvature,

σ=p·R

it can be expedient, at least on the side of the higher pressure, i.e.on that of the covers 6, to insert a cross-piece 17 which connects theupper chord 11 with the lower chord 12 of each tension-compressionelement 1 here vertically and parallel to the plane of thetension-compression bars 2 and tension straps 4 on the side of thehigher pressure. Such a cross-piece does not need to be gas-tight, ifthe air chambers 16 are themselves gas-tight. The cross-piece isconstructed so that it does not prevent the folding of the system.

An analogous example embodiment to that of FIG. 10 is illustrated inFIG. 11. It is based on a triangular basic grid corresponding to that ofFIG. 9. An outer frame, constructed on three tension-compressionelements 1 each with a half cover 6, for example again each with anelastic hollow member 5 (not visible), carries a flat arrangement oftension-compression elements 1 crossing over each other according to oneof the preceding corresponding example embodiments. The knots 9 lierespectively on this outer frame. In the present illustration, thus 16triangular chambers are formed, which are again constructed as airchambers 16. The boundary areas to the half covers 6 can again containcross-pieces 17, in order to prevent a passage of the hollow members 7through between the tension straps 4.

In a further example embodiment according to FIG. 12, as a supplement tothat of FIGS. 1, 5, 6 and 7, further tension-compression bars 2 areincluded. These run respectively from a joint 3 in the upper chord 11 tothe joint 3, adjacent to the right and/or to the left, in the lowerchord 12. These do not prevent the folding process, but can increase therigidity of the tension-compression element, depending on the case ofload, by receiving compression forces.

FIG. 13 to 15 are illustrations of a further areal support framework,here in the form of an umbrella 22. In FIG. 13 a a stand 21 isillustrated, on which a number of foldable tension-compression elements,for example according to FIG. 1, is articulatedly connected, at least ina knot, the inner knot 9. The joint 3 lying beneath the inner knot 9 inFIG. 13 a can rest on the stand 21 or can be fastened so as to bemovable to a limited extent. FIG. 13 b shows the tension-compressionelements 1—without the pneumatic elements 5—in the unfolded and extendedstate. FIG. 13 c shows the umbrella 22 in plan view. A first variantembodiment according to FIG. 13 d shows how each tension-compressionelement 1 is surrounded by two pneumatic elements 5, as illustrated inFIGS. 2 and 3. In this variant embodiment, a membrane 14 is included inbetween the individual tension-compression elements 1, which membrane 14is tensioned by the filling of the pneumatic elements, together with theunfolding of the tension-compression elements 1.

FIG. 14 shows a second variant embodiment. The field between twoadjacent tension-compression elements 1 is respectively filled by asingle pneumatic element 5, which provides both for the tensioning ofthe tension straps 4 and also for the lateral stabilizing of thetension-compression elements 1.

In FIG. 15 a third variant embodiment of the umbrella 22 is illustrated.Here, cross-pieces 23 are included into the pneumatic elements 5, whichcross-pieces 23 in each case connect the under and upper sides of thecover 6 with each other. Hollow members 7—optionally elastic—areinserted for example again between the cross-pieces 23. Compared withthe second variant according to FIG. 14, this third variant has theadvantage of being substantially thinner in construction.

The pressure gas with which the hollow members 5 are filled can becompressed air or another gas. The gas can be heavier than air—forexample CO₂—or lighter than air, such as for example so-called balloongas or hydrogen.

1. A pneumatic support structure with a tension-compression element (1)and two pneumatic elements (5) able to be filled with compressed air,which are arranged on both sides of the tension-compression element (1),characterized in that the tension-compression element (1) consists of anupper chord (11) and a lower chord (12), which are united in a knot (9)at each end of the tension-compression element (1), both the upper chord(11) and also the lower chord (12) consist of tension-compression bars(2) joined together in joints (3), the upper chord (11) and lower chord(12) are connected by tension straps (4) which are fastened in the upperchord (11) and/or in the lower chord (12) in the region of the joints(3), the two pneumatic elements (5) are elongated and their diametertransversely to the length is greater than the distance of upper chord(11) and lower chord (12), such that on filling of the pneumaticelements (5) with a pressure gas, tensile stresses occur in the covers(6), which generate forces in the plane of the tension-compressionelement (1) which preload the tension straps (4) and thereby stabilizethe joints (3) and also secure the tension-compression bars (2) againstbending out and/or in, the tension-compression element and the pneumaticelements (1) are foldable in the state of the pneumatic elements (5)when not filled with pressure gas, the support structure, consisting ofthe tension-compression element (1) and the two pneumatic elements (5)situated in a shared cover (6) can be erected from the emptied stateinto the state ready for operation, by filling with pressure gas.
 2. Thepneumatic support structure according to claim 1, characterized in thatthe two pneumatic elements (5) are connected and form a single pneumaticelement (5).
 3. The pneumatic support structure according to claim 2,characterized in that the pneumatic element (5) is identical to thecover (6).
 4. The pneumatic support structure according to claim 1,characterized in that each of the two pneumatic elements (5), which areeach arranged on one side of the tension-compression element (1),consists of the cover (6) and of an air-tight hollow member (7).
 5. Thepneumatic support structure according to any of the preceding claims,characterized in that the hollow members (7) consist of an elasticmaterial.
 6. The pneumatic support structure according to claim 1 to 3,characterized in that the connections of the tension-compression bars(2) adjoining the knots (9) must be loosened, in order to be able tofold the tension-compression element (1) and the pneumatic supportstructure.
 7. The pneumatic support structure according to claim 1 to 3,characterized in that the joints (3) in the upper chord (11) of thetension-compression element (1) are situated at the homologouslocations, such as those of the lower chord (12), and the said joints(3) are respectively connected by a tension strap (4) fastened in eachjoint (3).
 8. The pneumatic support structure according to claim 1,characterized in that the tension straps (4) are fastened on the joints(3).
 9. The pneumatic support structure according to claim 7,characterized in that all the tension straps (4) are of equal length,upper chord (11) and lower chord (12) run substantially parallel to eachother.
 10. The pneumatic support structure according to claim 7 or 8,characterized in that the length of the tension straps (4) increasesfrom the knots (9) towards the centre of the tension-compression element(1), both upper chord (11) and lower chord (12) describe a curved shapeand with the exception of the outermost tension-compression bars (2) ofthe lower chord (12), which have a length b, all the tension-compressionbars (2) have an identical length l and the condition b>l is maintained.11. The pneumatic support structure according to claim 10, characterizedin that the centres of the tension-compression bars (2) of the upperchord (11) are situated at the homologous locations, as the joints (3)of the lower chord (12), and the centres of the tension-compression bars(2) of the lower chord (12) are situated at the homologous locations, asthe joints (3) of the upper chord (11), and the said centres of thetension-compression bars (2) of the upper chord (11) are connected withthe joints of the lower chord (12), and the said centres of the lowerchord (12) are connected with the said joints of the upper chord (11)with tension straps (4).
 12. The pneumatic support structure accordingto claim 11, characterized in that all the tension straps (4) are ofidentical length, upper chord (11) and lower chord (12) runsubstantially parallel to each other.
 13. The pneumatic supportstructure according to claim 11, characterized in that the length of thetension straps (4) increases from the knots (9) towards the centre ofthe tension-compression element (1), both upper chord (11) and lowerchord (12) describe a curved shape and with the exception of theoutermost tension-compression bars (2) of the upper chord (11), whichhave a length b, all the tension-compression bars (2) have an identicallength l, and the condition h*>l/2 is maintained, where h* is the lengthof the outermost tension straps (4) on both sides of thetension-compression element (1).
 14. An areal support framework withpneumatic support structures according to any of claims 1 to 13,characterized in that at least three such pneumatic support structuresare connected with each other and a membrane (14) is spanned between thepneumatic support structures.
 15. The areal support framework withpneumatic support structures according to claim 14, characterized inthat the pneumatic support structures are connected with each other intheir knots (9).
 16. The areal support framework with pneumatic supportstructures according to claim 14, characterized in that fourtension-compression elements (1) are arranged in a quadrilateral and arerespectively connected with each other at their knots, two furthertension-compression elements (1) are present and run respectively fromcentre to centre of the first four tension-compression elements and restthere with their knots (9), externally on the four first-mentionedtension-compression elements (1) in each case a cover (6) is arrangedwith a hollow member (7), and is connected with the tension-compressionelement (1), the four fields between the total of sixtension-compression elements (1) each contain an air chamber (16) whichis likewise gas-tight and can be filled with compressed air.
 17. Theareal support framework with pneumatic support structures according toclaim 16, characterized in that the air chambers (16) are closed off ina gas-tight manner with respect to the hollow member (7).
 18. The arealsupport framework with pneumatic support structures according to claim14, characterized in that a plurality of tension-compression elements(1) is present, in which respectively three of these tension-compressionelements (1) are arranged in a triangle and are connected with eachother in their knots (9), the said plurality of tension-compressionelements (1) is dimensioned so that, arranged in the area, they againform a triangle with each other, with an outer frame, this said outerframe consists of a total of three tension-compression elements (1),which are connected with each other in their knots (9), the furthertension-compression elements (1) rest respectively with their knots (9)on the said three tension-compression elements (1) and cross each otherwhere necessary, the tension-compression elements (1) forming the saidouter frame have on their outer side in each case a cover (6) with ahollow member (7), which cover (6) is connected respectively with theassociated tension-compression element (1), the triangular fieldsbetween the sections of tension-compression elements (1) respectivelyeach contain an air chamber (16), which is likewise gas-tight and can befilled with compressed air.
 19. The areal support framework withpneumatic support structures according to claim 14, characterized inthat the at least three pneumatic support structures are articulated ineach case with one of their knots (9) on a stand (21) and pointsubstantially radially outwards therefrom, the first joint (3) of thelower chord (12) rests on this stand (21), the areal support frameworkwith the stand (21) forms an umbrella (22) which is tensioned by fillingwith compressed air and can be folded by emptying.
 20. The areal supportframework with pneumatic support structures according to claim 16,characterized in that the pneumatic elements (5) respectively take upthe entire intermediate space between adjacent tension-compressionelements (1).
 21. The areal support framework with pneumatic supportstructures according to claim 17, characterized in that the pneumaticelements (5) have substantially vertical cross-pieces (23), whereby theoverall height of the pneumatic elements (5) is reduced.
 22. Thepneumatic support structure according to any of claims 1 to 13,characterized in that the pneumatic element (5) is filled with a gas,which is heavier or lighter than air.
 23. The areal support frameworkwith pneumatic support structures according to any of claims 14 to 21,characterized in that the pneumatic elements (5) are filled with a gaswhich is heavier or lighter than air.